This study will investigate the actions of the larynx involved in different phonation types, relating them to acostic attributes of the sounds produced. Voice qualities are hard to describe in objective terms, partly because observers often do not agree on what counts as an exemplar of a particular voice quality. However, a wide range of phonation types can be classified in linguistic terms. Speakers of many languages differentiate words by means of the consistent use of "breathy" or "creaky" types of voice that occur in English only in the speech of those who have voice disorders. This research will correlate the physiological properties of these contrastive sounds with simultaneously obtained acoustic measures. Preliminary studies will be conducted on about 60 languages. From these at least 12 languages that have non-English phonation types will be investigated. Ten speakers of each language will be used. The physiological properties to be investigated include the distance between the arytenoid processes and the glottal area, as observed through fiberoptic techniques, and aerodynamic measures such as the ratio of the glottal air flow, and the transglottal pressure. The acoustic analyses will include measurement of jitter (period to periopd irregularity), spectral balance (e.g. the energy in the first formant compared with that in the fundamental), and measurements of the recovered glottal pulse shape (e.g. the duty cycle and the sharpness of the glottal closure). Speech pathologists and laryngologists will benefit from detailed studies of these linguistically classified phonation types. The data will also be important in studies of the full range of the capabilities of the normal human larynx.